The interaction of light with semiconductor devices is at the core of many important innovations. Semiconductor photodetecting devices, such as photovoltaics, photodiodes, imagers, are used in various technologies for example, solar cells, digital cameras, optical mice, video cameras, video game consoles, cell phones, and the like. Silicon is the most prevalent semiconductor for electronic devices, and is also very widely used for optoelectronic devices such as optical detectors, image sensors and solar cells. The bandgap of silicon at room temperature is 1.12 eV, and in general semiconductors do not absorb photons that have energies below their bandgap energy. However, there are many applications that require optical detection at lower energy levels than silicon's bandgap. Of particular interest, for example, are the energy levels 0.95 eV (1310 nm) and 0.8 eV (1550 nm). These applications are typically served by other semiconductors with smaller bandgaps, such as germanium, indium gallium arsenide, mercury cadmium telluride and the like.